I imported a robotic arm 3ds model to play with and it came in with these little nodes. I think they are vertex groups but I don't know how to play with these because I dont know what to call them to search in google for a tutorial.

I tried to delete the nodes so that I could attempt to build an armature system. But, when I did, it deleted parts of the mesh.

Rotating or moving the nodes cause parts of the mesh to move, but not in the way they should. For example, clicking on the node that is associated with the top arm and rotating does not cause the arm to rotate as if it was attached to the lower arm. It just moves independently.

Since they look like origin points, I tried to set the origin to mesh. But the node didn't move.

There are no dope sheets or curves associated with the model.

How can I set this up so that it works properly?

How do I delete these nodes without deleting the mesh, if I wanted to start over? Or how can I convert these to bones?

Where should I start to look? (I have watched tutor4's animation tutuorial at https://www.youtube.com/watch?v=xy8yFclpC9E but all it did was make me want to make my own bones for the model.)

robotic arm model screen shot


Short Answer: You will probably have to manually fix and rig your object by hand

Long Answer

3DS File format is a very basic and old interface file format, with antiquated features and limited capabilities.

It does not support many organization structures, nor does it doesn't support animation, rigging, armatures or vertex groups. I am not even sure if it supports any type or hierarchy at all like parenting; and it certainly doesn't support Blender specific features like vertex groups.

Bottom line is if you only imported your model directly from a 3Ds file those can't possibly bones nor any type of control for your objects.

The objects you show selected in your screenshot are of Mesh type, you can tell from the Properties Window active Object Data icon.

My blind guess is, from the look of your model is that it was somehow modeled in some sort of CAD-like software with iether NURBS or ACIS Solid based geometries, which often don't support Blender-like traditional rigging systems either.

Those types of software also often don't have a concept of "object centers* or explicit "origin points" nor "local coordinate systems", which often results in objects not having a specific, or expected origin or pivot of transformation when imported into mesh based modelling applications like Blender.

So even if those centers were successfully imported there is no guarantee they would get where you need them to be by default.

Those may be stubs or remains of any CAD specific structures that were left over while exporting the model, as much as they can be representative of some sort or "object origin" from the origin application.

Bottom line is, if you want to animate this you will probably have to manually assign correct origins to all your objects one by one, parent them properly, and create your own skeleton or constraints based rig.

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